This invention relates to a recording and/or reproducing device having a recording member for storing and filing information. In particular, the invention is directed to an apparatus for rotatably supporting a recording member.
Such recording and/or reproducing devices are constructed of a turntable for receiving and supporting a recording member. A light beam is utilized to record and reproduce information (e.g., video) on the recording member. Recently, there has been a demand for increasing the information storage capacity on the recording member. To meet this demand, disc units having the capability of recording information on, and reproducing information from, both sides of the recording member have been developed. As shown in U.S. Pat. No. 4,074,282, for example, a disc unit having two spaced and centrally apertured recording portions are utilized. Each recording portion is provided with a recording layer on its inner surface. The disc unit is loaded onto a turntable which rotatably supports the disc unit. The turntable includes a perpendicularly orientated centering member which protrudes through the apertures of both recording portions. The construction of the disc unit and its position on the turntable permits recording and reproducing information on the recording layer on each side of the recording member.
It is essential when utilizing this kind of disc unit for recording and reproduction that it be correctly and precisely positioned on the turntable. The recording surface of the recording member must be substantially parallel to the surface of the turntable. This is very important during reproduction of the information since the light beam which detects the information must correctly and precisely contact the areas of the recording member where the desired information is located. Any tilting of the recording member with respect to the turntable will cause defective reproduction and recording. Therefore, the aperture in each recording portion must coincide with the centering member on the turntable. Consequently, it is necessary to precisely align the apertures in the two recording portions in order that the surface of the disc unit is positioned substantially parallel to the surface of the turntable.
In practice, however, due to errors which arise during production of the disc unit, it is not possible to precisely align the apertures. As a result, it is impossible, in many cases, to load the disc unit onto the turntable due to mismatching of these apertures. Further, tilting of the recording member will occur with respect to the turntable due to this misalignment. Such misalignment will prevent accurate reproduction and recording.